Conventionally, frequency arrangement for a new service or frequency arrangement for a new provider has been made under the control of the government.
In particular, if there are new providers, a new frequency may be allocated through auction or the existing frequency may be collected from the existing provider and then rearranged for another provider to distribute frequencies of limited resources.
However, with the recent spread of various wireless Internet based applications such as opened user equipment platform, application store, and mobile VoIP, the demand of radio data traffic has been increased rapidly. For this reason, frequency distribution under the control of the government was very inefficient, and it has been gradually difficult to ensure new frequency on a frequency distribution table.
In particular, with the rapid growth of broadcast and communication systems, a next generation communication system has been designed in the form of combination of various networks, the system has been gradually complicated, and the need of interworking has been gradually increased. Also, as the communication technology and services are developed, the usage frequency for frequency resources has been increased. As a specific spectrum band is fixedly reserved for excellent communication technology and service, the problem of the spectrum scarcity is becoming a big issue.
Recently, as a method for solving such a problem, a spectrum sharing scheme has received attention. The spectrum sharing scheme is based on the aspect that the spectrum scarcity may be solved through sharing although the spectrum is scarce on the spectrum distribution table as the current spectrum scarcity is based on the existing partitioning spectrum control scheme.
As the problem of the spectrum scarcity is recognized as the important issue all over the world, on the November of 2008, the US federal communications commission (FCC) has decided to apply the cognitive radio technology which is the spectrum sharing technology to TV idle spectrum (white space) to increase spectrum usage efficiency and facilitate the introduction of a new service and then has amended the related rule.
As this action has been gradually enlarged, the UK has allowed to use the cognitive radio (CR) based spectrum sharing technology at a band of TV broadcast bands, which is not used spatially, that is, white space band, in 2009, the EU is currently discussing the introduction of the CR based spectrum sharing technology, and the South Korea is also preparing for the policy for the spectrum sharing based on the white space band.
The cognitive radio technology refers to a system that allows a communication device to observe a communication status by itself, to determine and select an action mode for optimized communication, and to make a plane for the later determining procedure from the previous communication experience.
In other words, the cognitive radio technology is the technology that discovers an idle resource (spectrum hole, white space) of spectrum bands allocated to an unlicensed band, and uses the idle resource in an adaptive and opportunistic way, wherein the idle resource is not used in time and space and its availability is low. At this time, if a primary user having the license for the corresponding band is discovered, the cognitive radio system should immediately stop use of the corresponding band or control a transmission power so as not to interrupt the primary user.
However, there have not been suggested detailed technical methods for discovering the idle resource (spectrum hole, white space), of which availability is low or which is not used in time and space, and using the idle resource efficiently without interference with a neighboring homogeneous or heterogeneous system.